Moving a player (GameObject) with WASD

The code below is attached to the player object.

Using WASD you can move the cube in the following directions

• W - Forward
• A - Left
• S - Backward
• D - Right

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class PlayerController : MonoBehaviour
{
    float speed = 5.0f;
    // Start is called before the first frame update
    void Start()
    {
        speed = 5.0f;
    }

    // Update is called once per frame
    void Update()
    {
        if (Input.GetKey(KeyCode.W))
        {
            transform.Translate(Vector3.forward * Time.deltaTime * speed);
        }
        if (Input.GetKey(KeyCode.S))
        { 
            transform.Translate(-1 * Vector3.forward * Time.deltaTime * speed);
        }
        if (Input.GetKey(KeyCode.A)) { 
            transform.Rotate(0, -1, 0);
        }
        if (Input.GetKey(KeyCode.D))
        {
            transform.Rotate(0, 1, 0);
        }
    }
}